Gas system for firearms



J y 1959 F. P. REED 7 9 3 GAS SYSTEM FOR FIREARMS I v Filed May 8 1957 7 I INVENTOR. :E'rederink EH51: :1

United States atent "ice GAS SYSTEM FOR Frederick P. Reed, Ludlow, Mass., assignor to the United States of America as represented by the Secretary of the Army Application May 8, 1957, Serial No. 657,990

2 Claims. (Cl. 89-191) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to firearms and more particularly to gas systems for the automatic operation thereof.

It is an object of this invention to provide for firearms a gas-operated actuating system whereby none of the parts is moved until after exit of the projectile from the barrel to disturb the aim of the firearm.

It is another object of this invention to provide for firearms a gas system whereby gases are trapped in a storage chamber during travel of the projectile of a cartridge exploded in the barrel down the bore thereof with the trapped gases being released for actuation against a piston after the exit of the projectile from the barrel.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing in which:

Fig. 1 is a cross-sectional side view of the gas system with the bore at atmospheric pressure and the valve in normal position; and

Fig. 2 is a view similar to Fig. l but showing the valve actuated by the pressure of the gases produced when a. cartridge is fired and the projectile is moved past the port leading to the gas system.

Shown in the figures is a firearm barrel 12 having a bore 14 therein. Mounted to barrel 12 is a gas device 16 having a housing 18 with a pair of spaced collar portions 20 which encircle the barrel to fix the gas device thereto. A pin 22 traverses each of the collar portions 20 and are received by accommodating channels in barrel 12 to secure gas device 16 thereto against displacement. Provided in the rear end of housing 18 is a gas cylinder 24 in which a piston 26 is slidingly mounted and a chamber 28 is provided in the front end of the housing in axial alignment with the gas cylinder.

A passageway 30, coaxial with gas cylinder 24 and chamber 28, provides communication therebetween and such passageway is in communication with a bore 32 which extends vertically downward from the top of housing 18 to align with a gas port 34 of similar diameter which extends through barrel 12 to bore 14. The top of bore 32 is counterbored, as noted at 36, to form an annular shoulder 38 and a plug 40 provided with a cylindrical portion 42 of reduced diameter on the underside thereof is threadably received by the top of such counterbored portion.

Mounted in bore 32 and counterbored portion 36 is a valve member 44 having a stem portion 46 which is slidingly received by such bore and a head portion 48 which is slidingly received by such counterbored portion. A cylindrical lug portion 50 is provided on the top of head portion 48 so as to engage cylindrical portion 42 and establish the up position of valve member 44. A helical coil spring 52 is mounted between head portion 48 and plug 40 to bias valve member 44 downwardly and such spring is prevented from reaching solid height by the con- 2,895,383 Patented July 21, 1959 54 which is disposed on such stem portion so as to align with passageway 30 when valve member 44 is in down position and thereby open communication between cylinder 24 and chamber 28, and such passageway and groove are so dimensioned that such passageway is blocked by the stem portion when the valve member is in the up position.

Extending diagonally between the lower portion of bore 32 and chamber 28 is an aperture 56 which is blocked by stem portion 46 when valve member 44 is in down position and is unblocked when such valve member is in the up position. Vents 58 provide communication between chamber 28 and that portion of the counterbored portion 36 which is between head portion 48 and plug 40 when valve member 44 is in top position.

Thus, when a cartridge is fired in barrel 12 the resulting gases enter port 34, after the cartridge projectile has passed thereby, to act against the bottom of stem portion 46 and force valve member 44 to up position against the bias of spring 52. With valve member 44 in up position, the mouth of aperture 56 is unblocked permitting the gases to proceed along such aperture in to chamber 28. However, as passageway 30 is blocked by stem portion 46 the gases entering chamber 28 are blocked from acting against piston 26.

When the cartridge projectile leaves bore 14 there is a rapid reduction of the gas pressure in the bore whereby the superior pressure of the gases in chamber 28 acting against the top of valve member 44 through vents 58, and the bias of spring 52, actuates valve member 44 to down position. With valve member 44 in down position, aperture 56 is blocked trapping the gases in chamber 28 and communication is opened between the chamber and gas cylinder 24 whereby such trapped gases are now permitted to enter cylinder 24 and energize the piston for actuation thereof.

From the foregoing, it is clearly apparent that there is herein provided a gas system which actuates the operating mechanism for a firearm after the exit of the cartridge projectile therefrom so as not to disturb the aim thereof with such gas system being simple and rugged in construction and positive in operation.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. In a firearm having a barrel with a bore and a gas port leading therefrom, a gas-operated actuating system including a cylinder, a chamber, a piston slidingly mounted in said cylinder, a passageway between said cylinder and said chamber, an aperture for directing gases from the bore to said chamber, a valve aotuatable by the difference in the pressure of the gases in said chamber and the bore, and stem means on said valve disposed for cooperation with said passageway and said aperture for unblocking said aperture to permit passage of gases into said chamber when the pressure of the gases in the bore is greater than that of the gases in said chamber and for simultaneously blocking said aperture and passing the gases in said chamber through said passageway to said cylinder for energizing said piston when the pressure of the gases in said chamber is greater than that of the gases in the bore.

2. In a firearm having a barrel with a bore and a gas port leading therefrom, a gas-operated actuating system including a cylinder, a chamber, a piston slidingly mounted in said cylinder, a passageway between said 3 4 cylinder and'said chamber, an aperture for directing gases groove in said valve alignable with said passageway when from the bore to said chamber, a valve movableto'an'up "said" valve is 'inthedown position for 'unblocking said position when the gas pressure in the bore is greater than passageway. that in said chamber, and to a down position when the pressure in said chamber is greater than that in the bore, 5 References Cited in the file of this Patent a stem portion on said valve for blockingsaid'aperture UNITED STATES PATENTS when said valve is in the down position and simultane- 2,149,512 Eiane Mar. 7, 1939 ously unblockmg said aperture and blocking sald passage- 2,845,008 Atwood July 29, 1958 way when said'valve is in the up position, and an annular 

